ENZYMES OF AMINO ACID METABOLISM IN NORMAL HUMAN SKIN .2. ALANINE AND ASPARTATE TRANSAMINASES

[摘要] A sensitive and reproducible micro method for the determination of alanine and aspartate transaminase activities in epidermal homogenates and various parts of skin (0.5 to 5 [mu]g dry weight) is described. Alanine transaminase activities of epidermis, dermis, hair follicle, sebaceous gland, and sweat gland in normal human skin were 0.37, 0.006, 0.15, 1.4 and 0.17 molesAg dry weight/hr respectively (average of 6 cases). Epidermal homogenates have an alanine transaminase activity of approximately 0.13 moles/kg wet wtAr. Aspartate transaminase activities of epidermis, dermis, hair follicle, sebaceous gland and sweat gland in normal human skin were 1.1, 0.03, 1.7, 3.6 and 2.6 respectively (average of 2 cases). Localization patterns of these 2 transaminases are similar, i.e., sebaceous glands contain the highest activities, 3.5 times more than epidermis. This pattern also is somewhat similar to that of isocitrate dehydrogenase activity previously described. It coincides with a product and substrate relationship among these 3 enzymes. Assay of transaminases in different types of hair follicles showed that alanine transaminase activity is 100% greater in anagen than in telogen or vellus type hair follicles. Alanine transaminase reflects more sensitivity to the functional status of the hair cycle than does aspartate transaminase. The active participation of alanine and aspartate transaminases in various functional statuses of skin and appendages.